ron v. sommeren
09-05-2002, 06:57 AM
http://www.torquemax.de/images/MeinMotor29.jpg http://www.torquemax.de/images/MeinMotor28.jpg
These do-it-yourself brushless outrunners can be made using a relatively simple lathe. The lrk/sps principle used here, features a high torque at lower rpm than a conventional high-revving brushless layout. There's no need for a gearbox, which means less weight, less losses, lower costs and no gear whining. It can be tailored to the application's needs by choosing the right stator diameter, magnet length and number of windings. There’s also the choice between a star (Õ) or delta (Ä) configuration. It’s possible to switch between these wiring types anytime: two ‘characteristics’ in one motor. It's also possible to rewind the motor (or even swap the complete stator) for a different type of application.
On the e-mail discussion homepage (www.yahoogroups.com/group/lrk-torquemax) you'll find links to outrunner sites and a FAQ with more links, tricks, pictures and material (magnets and stator!) suppliers. You can also join the discussion there:
www.yahoogroups.com/group/lrk-torquemax
The outrunner is an inside-out motor, the coils are stationary, housing and magnets rotate. This has the additional benefit of good magnet cooling and the coils are not stressed by centrifugal forces. The magnets must have at least a magnetic strength of 1.1 Tesla (Neodymium, NdFeB, magnets). The motors built to date, range from slow-flight 20Watt to 2kW and helicopter applications, development for 3kW versions is underway. Efficiency is in the 80-85% region and still increasing, slowly moving to 90%. Outrunner motors operate with normal brushless controllers although some are better suited than others. ESC manufacturers have already updated or are in the process of updating their controller software to make the controllers suited for this type of motor.
You can use an old brushed motor or gut your CD-ROM player, harddisk, wife's blowdryer (or your own ;), powertools (cordless) or fanmotor for stator material. Check the bin of a motor/transformer rewind shop for material. You can do a little dumpster jumping at metal stampers, scrap yards, the local dump. Use shafts from VCR’s or broken drills. Or you can buy the parts.
These do-it-yourself brushless outrunners can be made using a relatively simple lathe. The lrk/sps principle used here, features a high torque at lower rpm than a conventional high-revving brushless layout. There's no need for a gearbox, which means less weight, less losses, lower costs and no gear whining. It can be tailored to the application's needs by choosing the right stator diameter, magnet length and number of windings. There’s also the choice between a star (Õ) or delta (Ä) configuration. It’s possible to switch between these wiring types anytime: two ‘characteristics’ in one motor. It's also possible to rewind the motor (or even swap the complete stator) for a different type of application.
On the e-mail discussion homepage (www.yahoogroups.com/group/lrk-torquemax) you'll find links to outrunner sites and a FAQ with more links, tricks, pictures and material (magnets and stator!) suppliers. You can also join the discussion there:
www.yahoogroups.com/group/lrk-torquemax
The outrunner is an inside-out motor, the coils are stationary, housing and magnets rotate. This has the additional benefit of good magnet cooling and the coils are not stressed by centrifugal forces. The magnets must have at least a magnetic strength of 1.1 Tesla (Neodymium, NdFeB, magnets). The motors built to date, range from slow-flight 20Watt to 2kW and helicopter applications, development for 3kW versions is underway. Efficiency is in the 80-85% region and still increasing, slowly moving to 90%. Outrunner motors operate with normal brushless controllers although some are better suited than others. ESC manufacturers have already updated or are in the process of updating their controller software to make the controllers suited for this type of motor.
You can use an old brushed motor or gut your CD-ROM player, harddisk, wife's blowdryer (or your own ;), powertools (cordless) or fanmotor for stator material. Check the bin of a motor/transformer rewind shop for material. You can do a little dumpster jumping at metal stampers, scrap yards, the local dump. Use shafts from VCR’s or broken drills. Or you can buy the parts.